A new boat project is finally underway in the basement. The new design is the latest in a long line of ideas around a modular, cartoppable sailboat for the low wind conditions we see so often in the midwest.

Preliminary CAD model of a rototmolded tacking outrigger with a windsurfer rig.

This latest embodiment is inspired by a Polynesian-style Outrigger Canoe. The design started with the idea of eliminating the planing hull so common to small sailing dinghies in favor of a narrow displacement hull more appropriate for the light winds in our area. The design started as a series of projects around European and American style sail canoes of the late 19th century and included several projects in CAD, an early skin-on-frame (SOF) prototype and a strip-planked open design. This latest outrigger design was undertaken because the presence of one or more outriggers allows the design to remain stable in extremely low wind while allowing for an impossibly skinny hull. Wave-piercing bows were selected to help reduce the impact of powerboat wake on forward progress and sail shape during low wind sailing.

The image above is another screenshot from Solidworks. It shows my original plan for the mold of this boat, including the use of intersection curves to create cross sectional mold frames.

The design began in CAD. My intention is to eventually realize this boat as a rotomolded hull that can be outfitted with one or two outriggers to become either a tacking outrigger or small trimaran. To ensure that the hull geometry performs well — and for a certain amount of boat therapy — I undertook a strip-planked version of the hull using a build methodology that is a composite of Ted Moore’s (Canoecraft) and Robert Morris’ (Building Skin on Frame Boats) methods. This build methodology allows me to quickly create an internal rib structure using SOF framing methods and later plank it with strips to create a lightweight, hard-sided hull. The advantages of this method are low material cost, speed, and —because I’m only making one of these — minimal investment in a mold.

I had originally intended to create a multi-section plywood mold using multiple plywood frames in the manner of Canoecraft. Taken directly from my Solidworks model, these frames would provide maximum control over the form and ensure that it closely reflects the model. I moved away from this method to give myself some freedom to build using a more freeformed method. For this method, I created plywood molds for just the stem, stern and widest section of the boat. The photo above shows these molds and the strongback on which they’re mounted. I’ll follow up with more progress in subsequent posts.